Method of preparing a non-woven fibrous web

ABSTRACT

THE SPECIFICATION DESCRIBES A METHOD AND APPARATUS FOR FORMING A NON-WOVEN FIBROUS WEB, E.G. SUITABLY FOR PADDING OR STUFFING. A TOW IS SPREAD AND FED WITHOUT TENSION BY TWO ROLLERS, ROTATING AT DIFFERENT SPEEDS, ONTO A CONVEYOR BELT, AND A PUSHER BLADE EXTENDING OVER THE FULL WIDTH INTERMITTENTLY PRESSES ON THE TOW AND MOVES FASTER THAN THE BELT. THE RESULTING WEB IS SPRAYED WITH A BONDING AGENT WHICH IS THEN CORED.   D R A W I N G

Sept. 5, 1972 BQLLIAND ETAL 3,689,344

METHOD OF PREPARING A NON-WOVEN FIBROUS WEB Filed April 2, 1969 I 2Sheets-Sheet 1 Sept. 5, 1972 BOLUAND ETAL v 3,689,344

METHOD OF PREPARING A NON-WOVEN FIBROUS WEB Filed April 2. 1969 2Sheets-Sheet 2 ln venlora RDbQI'+ sol/48nd C audz Still .6 (Lshmgn "Y,QmZ 6 Cushmn A ttorneys United States Patent @1 3,689,344 PatentedSept. 5, 1972 ice 3,689,344 METHOD OF PREPARING A NON-WOVEN FIBROUS WEBRobert Bolliand and Claude Saligny, Lyon, France, as-

signors to Societe Rhodiaceta, Paris, France Filed Apr. 2, 1969, Ser.No. 812,646 Claims priority, appliiato ngll rance, Apr. 2, 1968,

Int. (:1. B29h 9704,- D04h 3/08 US. Cl. 156-181 4 Claims ABSTRACT OF THEDISCLOSURE The present invention relates to a method and apparatus forthe preparation of a non-woven fibrous web material.

In the present description, the expression non-woven fibrous webs refersto material, generally of a homogeneous nature, which may have largedimensions in two directions relatively to the third and which may beconstituted by continuous filaments or discontinuous fibres, alone or ina mixture, distributed unidirectionally or at random and the cohesion ofwhich is obtained by mechanical, physical or chemical means, or by acombination of such means.

For some decades, such material has been successfully used for manypurposes, e.g., trimming or lining, wadding, covers or blankets,garments, covering means for floors and walls, felts, filters andbackings. Material of this kind, it it is subjected to furthersubsequent treatment, such as needling and/ or calendering, may beutilised for purposes other than lining or stufiing. For example, itcould also be used as a wall covering, a covering for the ground, acoating backing or for garments.

When used as a lining or stufiing material in which it is more or lesscompressible and slightly elastic or resilient, this material isutilised for the stuffing of furnishing articles, such as pillows,cushions, eiderdowns, sleeping bags and the like. For this purpose usehas long been made of natural materials, such as down, feathers orhorsehair. It has also been proposed to employ discontinuous, crimpedchemical fibres, for example synthetic fibres, introduced alone or in amixture, in the form of wadding or a lap. Unfortunately, in course oftime and notably after washing, these fibres tend to protrude throughthe enveloping material and to agglomerate in the form of compact balls,which it is impossible to dissociate.

Recently, there has been proposed a novel stutling material constitutedby a highly, corrugated web of continuous chemical filaments, directedsubstantially in the same direction and wherein the undulations orcorrugations are fixed with the aid of an appropriate resin.

The method for the preparation of such webs consisted in passing, undertension, a tow of continuous filaments between two smooth rollers drivenat different peripheral velocities, taking up substantially withouttension the corrugated web thus formed, spraying a bonding agent on thesaid undulating lap and, finally, curing the bonding agent thusdeposited.

The method for the spreading out and undulation of the tow of continuousfilaments, which may or may not be crimped, by passage between tworollers rotating at different peripheral velocities does not permit theproduction of webs which have relatively plane external surfaces, suchas is desirable for the stufiing material or wadding used for stuffingcoverlets or bedspreads or quilted articles.

According to the invention there is provided a method of preparing anon-woven fibrous web, such method comprising feeding a towsubstantially without tension to a conveyor belt to which a continuousadvancing movement is imparted, displacing a pusher blade spaced fromsaid conveyor belt in the same direction and at a higher velocity thansaid conveyor belt, periodically to exert pressure on the entire widthof said tow and to subject said tow to local friction and thereby form aweb, taking up the web thus formed substantially without tension,spraying a bonding agent on the web and curing the bonding agent.

Preferably, the bonding substance is a crosslinkable resin which iscured by thermal treatment.

The previous spreading out of the tow may be effected by any appropriatemeans, notably by passage between two rollers rotating at differentperipheral velocities.

In the following description, the expression pusher blade will be usedto designate any means permitting the simultaneous exertion on thespread-out tow of pressure and also of friction. The tow used hassubstantially no twist or interlacing and includes a large number ofcontinuous filaments which may or may not be crimped. For example, usemay be made of any kind of tow manufactured from any artificial orsynthetic chemical material. Advantageously use is made of crimpedsynthetic filament tows, such as those based on polyamides (polyamide 6,6.6, 6.10, 11, etc.) on polyolefines (polypropylene) or on the vinylsubstances and derivatives. Moreover, good results have been obtainedwith tows based on polyester filaments (ethylene polyterephthalate) oracrylic filaments. In practice, the tow maybe stuffer crimped.Similarly, use may be made of tows comprising low-stretch filaments.

The invention also provides apparatus for preparing a non-woven fibrousweb, such apparatus comprising a conveyor belt, means for moving saidbelt at a given velocity, means for spreading a tow formed fromcontinuous filaments, and for feeding said tow onto said conveyor belt,a pusher blade spaced fromsaid conveyor, means for urging said pusherblade towards said conveyor belt and for moving it parallel to said beltat a velocity higher than said given velocity, means for removing theweb thus formed from said conveyor belt, means for spraying a bondingagent onto the thus formed web, and means for curing the bonding agent.

Finally the invention provides material produced by the method, usingthe apparatus, according to the invention.

In order that the invention may more readily be understood, thefollowing description is given, merely by way of example, referencebeing made to the accompanying drawings, in which:

FIG. 1 is a side elevation of one embodiment of apparatus according tothe invention;

FIG. 2 is a diagrammatic view of a portion of the apparatus of FIG. 1,showing the movement and action of the pusher blade on the tow;

FIG. 3 shows modification of the pusher blade arrangement; and

FIG. 4 is a diagrammatic illustration of the web obtained.

Referring to FIG. 1, a tow 1 is dotted from a conventional storagecarton 2, and it is progressively converted to a web of filaments, withthe aid of spreaders having curved bars 3 and tensioners 4.Subsequently, by braking the tow, notably with the aid of a series ofbars 5, the tow is introduced under tension between two cylinders orrollers 6 and 7, the spacing of which is adjustable as a function of thenature and thickness of the fibrous web and the degree of tension whichit is desired to impart thereto, the said cylinders rotating atdifferent peripheral velocities so as to complete the spreading; then,the web thus formed is received, preferably without tension, on aconveyor belt 8 displaced at constant velocity and on which it adheresunder the influence of friction. Preferably, a belt will be used, thesurface of which is made of a material having a high coefficient offriction.

The web conveyed by the belt 8 is then subjected to the action of apusher blade 9 which intermittently exerts pressure on the web over theentire width thereof and subjects it to localised friction, the pusherblade being displaced in the same direction but at a higher velocitythan the belt. The movement of the pusher blade is imparted by anyappropriate means such as cams, illustrated diagrammatically as a driveassembly 10 in the figure. The thus formed web then leaves the conveyorbelt 8 and is taken up, practically without tension, on a secondconveyor belt 11 the velocity of which is regulated as a function of theoutput velocity of the web on the conveyor 8. It then travels into aspraying chamber 12 where there is deposited an appropriate resin whichis subsequently cured by passage through a heating chamber or oven 13.Advantageously, it will be possible to spray or atomise the bondingsubstance on the two faces of the lap. The proportion of resin in thelap is small and preferably does not exceed 10% of the weight of thelap.

The movement of the pusher blade 9 is shown diagrammatically in FIG. 2,wherein 1 represents the open tow, 8 the conveyor belt and 23 the lowerend of the pusher blade to which is imparted a movement, the extremepositions of which are designated A, B and C.

Depending on the textile material utilised, the angle of attack or ofthe pusher blade on the conveyor belt is adjustable, as is also theamplitude BC. Similarly, by modifying the travel path A-B, it becomespossible to increase or diminish the pressure exerted by the pusherblade on the web 1. Finally, the selection of the material from whichthe end of the pusher blade is manufactured depends, to a considerableextent, on the textile material to be processed. Good results areobtained with a pusher blade made of natural or synthetic rubber havinga Shore hardness between 35 and 80".

In practice, the angle a varies between 30 and 70, the amplitude BCbetween 1 mm. and 60 mm. and the number of cycles A-BC between and 200per minute. Drive to the rollers 6 and 7, to the conveyor belt 8 and tothe drive assembly 10, may be derived from a common drive motor 20.

In a modification illustrated in FIG. 3, a series of pusher blades 31act successively on the web, the pusher blades being mounted radially ona common spindle 32 to which a movement of continuous rotation isimparted by the drive motor 20, the distance between the spindle andconveyor belt 8 being adjustable relatively to the conveyor belt.

FIG. 4 is a diagrammatic illustration of the textile web formed inaccordance with the invention. It will be seen that the filaments 41exhibit a helical crimp and that the external surfaces 42 and 43 of theweb are substantially planar.

Although, generally, a single thus-treated web is utilised, it wouldalso be possible, for certain applications, to superpose a multiplicityof the said webs. Similarly, it maybe subjected to further treatmentprocesses, such as needling and/ or calendering, and the articleobtained may be employed for purposes other than stufiing.

The following example, which is given purely by way of non-limitativeillustration, shows the manner in which the invention may be applied.

EXAMPLE The installation shown in FIG. 1 was fed with a tow the totalcount of which was 222,222 dtex (200,000 denier), of ethylenepolyterephthalate filaments having a unit count of 1.65 dtex (1.5denier), and a crimp of 3-4 (number of undulations per centimetre). Thefeed velocity of the tow was 15 metres/ min. After passage through thespreaders 3, the tensioners 4 and the bars 5, the web formed had anaverage width of 200 mm. Opening was completed by passage between twocylinders 6 and 7 covered with a layer of rubber having a Shore hardnessof 65 rotated at peripheral velocities of 2 metres/min. and 18metres/min, the spacing thereof being adjusted at 0.2 mm. Then, theundulated web was deposited without tension on a conveyor belt 8 made ofrubber and travelling at a velocity of 4 metres/ min. It was thensubjected to the action of the pusher blade 9 the end of which was madeof rubber having a Shore hardness of 65 and the minimum distance ofwhich relatively to the conveyor belt was 0.1 mm. The angle of attack awas approximately 50 and the amplitude of displacement in a planesubstantially parallel to that of the belt 8 was 40 mm. The velocity ofthe pusher blade was regulated in such manner that it performed cylesA-B-C (as shown in FIG. 2) per minute, the end of the pusher blade beingdisplaced at a velocity close to 20 metres/min. The web thus formed wasreceived, without tension, on the conveyor belt 11 at a velocity of 5metres/ min. It weighed 50 g./ square metre, was 1 metre wide and 5 mm.thick, exhibited good cohesion and had substantially plane outer faces.After being received on the belt 11, it was continuously sprayed, at arate of 10 g./square metre, dry product, with a nonplasticised,crosslinkable acrylic resin in a 40% (dry extract) dispersion, in watercontaining an anionic surfaceactive agent. The crosslinking of the resinthus deposited was effected by drying, for 4 minutes at C. The lap wasthen wound-up on a spindle.

We claim:

1. A method of preparing a non-woven fibrous web, said method comprisingthe steps of:

(a) providing a conveyor belt;

(b) imparting a continuous advancing movement to said conveyor belt at agiven velocity;

(c) feeding a tow substantially without tension to said conveyor belt;

(d) intermittently displacing a pusher blade means spaced from saidconveyor belt in the same direction and at a controlled velocity whichis higher than that of said conveyor belt, for eflfectively exertingperiodical pressure on the entire width of said tow, at axiallydisplaced positions along the path of travel of said tow, to subject thefilaments of said tow to local friction, and thereby form a web havinghelically crimped filaments;

(e) taking up the web thus formed substantially without tension;

(f) spraying a bonding agent on said web; and

(g) curing the bonding agent thus deposited.

2. The method in claim 1, wherein the spacing from the conveyor belt andthe velocity of said pusher blade are adjustable.

References (Jited UNITED STATES PATENTS Powell 156371 Hosfield 156-55310 Houghton 156-370 Rodman 15662.2

6 6/ 1957 Dildilian 15662.2 6/1966 Makanse 156-166 2/1956 Frickert, Jr.156l81 X FOREIGN PATENTS 4/1949 England 156'62.2

BENJAMIN A. BORCHELT, Primary Examiner H. TUDOR, Assistant Examiner US.Cl. X.R.

